Current electronic mechanisms such as digital cameras often employ die-level opto-electronic devices to gather and process optical information. Such devices commonly comprise a single semiconductor die with a photonic device, such as a charge coupled device (CCD) or image sensors like complementary metal oxide semiconductor (CMOS) imagers, fabricated on its upper surface. This photonic device is then left optically exposed, where it can sense photonic input. In this manner, photonic devices can read and process visual input, generating digital images without need of lenses or film.
Such opto-electronic devices are, however, not without their drawbacks. The delicate circuitry of a photonic device must be protected from contaminants and damage, yet must also remain optically exposed. It is often preferable to protect these photonic devices from harm by encapsulating them within an optically transparent package. FIG. 1 illustrates a cross-sectional view of a typical leadless chip carrier (LCC) package that is often used to enclose die-level opto-electronic devices. A die 10 containing imaging circuitry is encased within a package 20. The die 10 also contains bond pads 11, and is wirebonded to terminals 21 with wires 12. The package 20 includes an optically transparent panel 22 that protects the die 10 from damage and contamination while still allowing its imaging circuitry to gather photonic input through the panel 22.
While this package 20 has a number of advantages, namely that it protects the die 10 and its delicate imaging circuitry without significantly detracting from its performance, the package 20 also has certain disadvantages. For instance, as the package 20 must leave sufficient space for the wires 12, it can be bulky. Also, because the package 20 offers no protection to the die 10 until the packaging process is complete, the die 10 remains susceptible to damage until then. Specifically, the die 10 and its imaging circuitry can be damaged at any time during wafer handling, dicing, or wirebonding.
It is therefore desirable to fabricate a more compact, die-level opto-electronic device that offers protection to its opto-electronic circuitry prior to encapsulation.